Poisoning in children causes great anxiety in parents and health
professionals alike.

Most cases of poisoning involve a child aged 1 - 2 years who
has swallowed a small amount of one substance. In adolescence
there is a second peak, due to deliberate self-poisoning. This
usually involves large quantities of medicines, recreational
drugs and ethanol, often taken together.

Accurate data on poisoning are hard to collect and scarce in
South Africa. Extrapolation from available figures1,2 suggests
that 200 000 - 300 000 child poisoning incidents
occur annually in the country. Less than 1% are fatal.
Globally, accidental poisoning causes about 4% of all
childhood deaths due to injury.3 In developing countries
the figure is likely to be higher.

Why the evidence base is
poor

In toxicology, reliable evidence on which to base decisions is
hard to find. Poisoned patients are a mixed group who often have
unreliable histories and may have been exposed to many toxins.
It is difficult to collect large case series of exposure to
similar toxins to yield reliable data with regard to
complications or mortality. Randomised comparisons between
management regimens need many subjects who have been exposed to
the same substance – therefore this is seldom feasible. Hard
end-points for comparing treatments, such as death, are rare;
consequently, surrogate markers, such as length of hospital stay
or administering an antidote, are often used. In some areas,
enough evidence has led to changes in treatment.

Gut decontamination

There has been a marked shift away from active gut
decontamination, such as induction of vomiting, gastric lavage
or administering activated charcoal; more emphasis is now
placed on supportive care. In 1997, the combined American and
European Academies of Clinical Toxicologists published new
guidelines.4 These emphasise that
patients can be managed successfully without aggressive gut
decontamination. Emptying
the stomach is no longer a routine part of the treatment of
poisoningand is
currently almost never used in children.

No technique of gut decontamination is risk free and it should
be reserved for potentially life-threatening doses and dangerous
toxins. Any form of gut decontamination may be unnecessary if
the patient has vomited the toxin spontaneously within minutes
of taking it. Timing is crucial. Gastric lavage has little
effect unless done within an hour of ingestion of the substance.
It is invasive and often causes vomiting and, sometimes,
aspiration. Before initiating gastric lavage, children have to
be sedated and an endotracheal tube has to be inserted.

Activated charcoal reduces the absorption of many organic
molecules, but it must be given within one hour to have a
significant effect. It is much safer than induction of vomiting
or lavage, but does not bind hydrocarbons, such as paraffin,
alcohols or metals. It is not used when caustic agents have been
ingested, because it may cause vomiting, which is particularly
dangerous in such cases, and because it makes endoscopy
difficult.

Common childhood
poisonings

Most of the agents involved in childhood poisonings are
medicines, with anti­depressants and analgesics being the most
common. Exposure to pesticides and household cleaning agents are
increasingly seen. In South Africa, paraffin (kerosene) remains
the single most frequent substance in childhood poisoning.2

Even though the list of ‘one pill can kill’ drugs5 is not
new, it is given below:

• oral hypoglycaemics

• beta-blockers

• calcium channel blockers

• tricyclic antidepressants

• alpha adrenergics, such as clonidine and
imidazolines

• chloroquine

• opioids, including
loperamide/diphen­oxylate (Lomotil and Imodium)

• salicylates.

Paraffin

Paraffin causes a chemical pneumonitis due to aspiration,
either during ingestion, after vomiting, or silently. These
children present with tachypnoea and an inflammatory response,
causing a fever and raised white cell count. Chest X-ray
findings do not correlate well with clinical signs; therefore
management must be based on clinical features. Treatment is
usually simple and brief, with supplemental oxygen being the
mainstay of supportive care. Gastrointestinal decontamination
and activated charcoal are contraindicated. A recent study6 has shown
that prophylactic antibiotics do not alter the outcome and
therefore must be reserved for cases of suspected secondary
bacterial infection 48 hours after ingestion.

Pesticides

In South African cities there has been a recent upsurge
in poisonings from pesticides bought from illegal street
vendors. These are often highly toxic organophosphates or
carbamates for controlled agricultural use, but sold illegally
as cockroach or rat poisons. They are unlabelled and highly
dangerous.7

Clinicians are familiar with the features of cholinergic
stimulation arising from organophosphate poisoning, which can be
reversed with atropine. A recent study8 has highlighted the
prevalence of poisoning with amitraz, which is often used as a
tick dip for livestock. It gives a similar clinical picture to
organophosphate poisoning, but without sweating, excessive
secretions, urinary and faecal incontinence or muscle
fasciculations. Treatment is symptomatic and supportive.

Paracetamol

Paracetamol poisoning is common. Toxic effects occur when the
amount taken exceeds the liver’s capacity to metabolise the
hepatotoxic metabolite. Poisoning may be from a single dose, but
attention has recently focused on the dangers of repeated high
doses, given over a number of days, to control pain or fever:
so-called repeated supratherapeutic ingestion. This pattern of
ingestion is particularly dangerous in adults and children over
the age of 6 years with chronic liver disease, malnutrition, and
HIV, and in users of enzyme-inducing drugs (e.g. carbamazepine,
phenytoin, rifampicin).

The decision to give the very effective antidote
N-acetylcysteine (NAC) is based on a serum paracetamol level
measured 4 hours after the ingestion of solid preparations
(2 hours after liquid preparations) and plotted on a treatment
nomogram. Clinicians who are familiar with the double parallel
line Rumack-Matthew nomogram will be pleased to know that it
has been simplified to a single curved line devised by a
consensus panel of Australasian toxicologists.9

Corrosives

Corrosive household products such as bleaches and drain
cleaners can cause significant injury. A recently highlighted
concern relates to the use of ‘laundry pods’ – packages of
detergent intended for one cycle of a washing machine or
dishwasher, often highly coloured and resembling a large
sweetie. Several incidents of serious poisoning have been
reported.10

Poison information

Clinicians who need help and advice on treating poisoning can
phone a Poison Centre (see the list below) or access the UCT
Poisons Information System (recently rebranded as AfriTox),
available in the Emergency Units of many hospitals countrywide.
Doctors can access AfriTox directly on computers or smart phones
and obtain information on the toxicity of chemicals, medicines,
commercial products and poisonous plants and animals, what
symptoms or signs to expect, and view detailed treatment
protocols.

• Information on subscribing to AfriTox by
e-mail: poisonsinformation@uct.ac.za

Summary

• It is estimated that 200 000 -
300 000 child poisoning incidents occur annually in South
Africa. Most cases involve a child less than 2 years of age
who has swallowed a small amount of one substance. Clinicians
should be aware of the ‘one pill can kill’ medicines.

• Emptying the stomach is no longer a
routine part of treating poisoningand
is currently almost never used in children. In
life-threatening poisonings, activated charcoal is safer than
emesis or lavage, but is usually only effective if given
within one hour of ingestion.

• Paraffin ingestion is still common in
children. Treatment is based on clinical features rather than
the chest radiograph. Activated charcoal is contraindicated
and prophylactic antibiotics do not alter the outcome.

• Unlabelled rat and cockroach poisons sold
on the streets contain highly toxic organophosphates and
carbamates. Poisoning with amitraz may present similarly to
organophosphates, but is treated symptomatically.

• Liver damage may follow repeated doses of
paracetamol given over days to treat fever at slightly above
the recommended dose or at shortened intervals.

• Information on the treatment of poisoning
is available on the telephone from poisons centres or by
accessing the web-based AfriTox Poisons Information System.